1. Field of the Invention
The present invention relates to keyboards or interface controls used as data input means for various electronic devices. More particularly, the present invention relates to a flexible electronic keyboard for portable electronic apparatus including industrial equipment, consumer products or appliances such as computers, telephones, musical instruments, toys, etc.
2. Description of the Prior Art
The miniaturization of electronic equipment has been a major focus in the research and development of these devices. In the case of portable electronic devices including personal computers, calculators, telephones and the like, miniaturization has been limited by the keyboard component. The keyboard component must have sufficiently large keys or keypads which are ergonomically feasible to the general population. Rigid keyboards, now in use, have fixed distance between the keys and/or between the switches to which the keys are physically connected. For this reason a full-sized keyboard presents a difficult design challenge to the miniaturization process. Use of the typical, full size keyboard would be self-defeating when applied to "notebook" or "laptop" computers, i.e.
Thus, because of their compact size, "notebook" and "laptop" computers have included keyboards of less than full size, i.e., the size of an average desktop general computer keyboard. Typically a laptop keyboard has a width of about 35 cm as opposed to an equally functional desktop computer keyboard having a width of 50 cm. Further, because the alphanumeric keys must be of a sufficient size to accommodate even large fingers, certain keys are often deleted or rearranged from their normal position on the keyboard as a sizing constraint. Such modifications can thus result in excessive motion and typing errors and can sacrifice available options associated with the missing conventional keys.
In the prior art the problem was addressed by reducing the size of the individual keys or by providing a modularly expandable keyboard. Although individual keys used in the typical keyboard could be reduced in size, such size reduction creates user difficulties in comfort and efficiency in operation.
U.S. Pat. No. 4,739,451 discloses a modularly expandable keyboard which has expansion modules capable of being integrated into a conventional keyboard.
U.S. Pat. No. 5,187,644 which is herein incorporated by reference describes a device comprising a monitor and an keyboard having one extendable flap for extending the keyboard to closely approximate a full size keyboard.
U.S. Pat. No. 4,950,874, which is herein incorporated by reference, discloses molded dome sheets which are used in electronic keyboards.
U.S. Pat. No. 4,952,761, which is herein incorporated by reference, discloses a touch contact switch which can be used in the present invention.
U.S. Pat. No. 5,141,343, which is herein incorporated by reference, discloses a keyboard assembly which can be compacted, protracted and adjusted to vary its size and the spacing between the keys thereof.
A disadvantage of known space adjusting keyboards especially for portable devices is that they either pose operating inconvenience or are prone to generating false signals, if the component parts are not properly aligned prior to use. Accordingly, there exists a need for a portable, fully functional electronic device having a light weight and a compact, substantially rigid construction, sufficient for substantially preventing false signals, but having a completely functional and full-sized keyboard, amenable to efficient use, but which can be readily compacted after use, for easy storage and/or transport.
Moreover, another problem has been noted in regard to conventional keyboards. Due to the orientation of the plane of a conventional keyboard relative to the orientation of the hands of its operator, the operator must hold his or her arms and hands in an unnatural and awkward position. Physicians have noted that prolonged periods of such activity can result in nerve disorders such as carpal tunnel syndrome.